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Arsenic poisoning

There is debate going on within the lumber industry in the USA about the use of inorganic arsenic as a wood preserver. Chromated copper arsenate (CCA) has been commonly used to preserve wood used for building materials for many years. Other preservatives containing inorganic arsenic include ACA and ACZA. Arsenic is a heavy metal which can build up in the system and cause several types of cancer, severe neurological damage and death in high doses.

Tests on various samples of CCA treated woods (see Environmental Working Group link below) have shown huge levels of arsenic exposure, well exceeding state limits. It is only necessary to touch treated wood to transfer the poison to your skin, from where it can be transferred to other parts of the body. The worst case is with children and in particular children's playgrounds, where a lot of contact may be made with the wood. If children put their hands in their mouth they can transfer the arsenic into their system.

Treehouse building using these treated woods presents a high risk of exposure to arsenic. Cutting, sanding and shaping this wood can produce poisonous sawdust which may be breathed in. Burning CCA-treated wood produces toxic fumes of arsenic and chromium and is illegal for this reason.

Since the end of 2004, CCA has not been permitted for use as a wood preservative for pre-treated lumber, but wood manufactured before this time may still contain arsenic.

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